Method for contact material regeneration



Jan. 4, 149. T. P. SHMPSON 2,458,433

METHOD FOR CONTACT MATERIAL REGENERATION Filed Nov. :50, 1945 2Sheets-Sheet 1 5 024; Jlmpaar;

INVENTOR. 7

BY Z %TTORNEY.-

1949. T. P. SlMPSON 2,45 33 METHOD FOR CONTACT MATERIAL REGENERATIONFiled Nov. so, 1945 2 Sheets-Sheet 2 I N V EN TOR.

We: 7? J 09 08 Patented Jan. 4, 1949 METHOD FOR CONTACT MATERIALREGENERATION Thomas 1. Simpson, Woodbury, N. 1., assignor toSocony-Vacuum Oil Company, Incorporated, a corporation of New YorkApplication November 30, 1943, Serial No. 512,324

7 Claims. 1

This invention has to do with method for conducting endothermic orexothermic reactions of fluid reactants in the presence of a moving massof particle form solid contact material which may or may not becatalytic to the desired reaction. Exemplary of the process of this kindis the regeneration of spent contact materials, previously used ascatalysts for the cracking conversion of hydrocarbons, it being wellknown that hydrocarbons of a gas oil nature boiling between about 500 F.and about 750 F. may be substantially cracked to gasoline, lighterhydrocarbons and limited amounts of heavy tarry materials by passingthem at reaction conditions of temperature and pressure such as forexample, temperatures of the order of 825 F. and above at pressuressomewhat above atmospheric in contact with a solid adsorptive catalyticcontact mass. The heavy tarry products, usually called coke, aredeposited upon the particle form contact mass thereby decreasing itsactivity and must be removed therefrom by some method such as hightemperature combustion with air. Usually the particle form contact masspartakes of the nature of fullers earth or natural or treated filteringclays and/or various synthetic associations of alumina, silica oralumina and silica, any of which may or may not have other constituentsadded for a purpose in connection with the processes such as certainmetallic oxides. In a most recent form this operation has developed asone in which the particle form solid contact mass material is movedcyclically throughtwo zones in' the first of which it is subjected toreaction and in the second of which it is subjected to the action of afluid regenerating medium such as a combustion supporting gas, acting toburn off contaminant materials deposited upon the contact mass duringreaction.

This invention has specifically to do with the operation and arrangementof reactor or regenerator vessels wherein reactions are conducted thenet thermal result of which is either the liberation or absorption ofheat in the presence of a moving particle form contact mass thetemperature of which is'maintained at desired levels in the varioussections or stages of said reactors or regenerators by the supply orremoval by an adequate means of the proper amount of heat to or from thevarious stages. Inasmuch as that part of reactors or regeneratorsdealing with the removal or supply of heat to the contact materialtherein involve the same fundamentals of application, construction andoperation, the term regenerator will hereinafter in thedescription ofthis invention and in claiming this invention be used in a sensesufliciently broad to include resupport reasonably rapid combustion ofthe contaminant material and below those levels which will have adetrimental effect upon the contact material activity by reason ofsintering or changing the form or composition of said contact material.The temperature level conducive of active regeneration as described isgenerally substantially higher than the minimum temperature which willsupport combustion in the same stage removed from the of regeneration,and the optimum temperature for a given burning rate tends to increaseas the amount of residual contaminant decreases.

Generally in the regeneration of contact ma-' terials such as those usedfor hydrocarbon cracking reactions, the composition and form of thecontaminant material changes as the burning thereof progresses, that is,as the contact material passes through the various sections of stages ofthe regenerator, resulting in the liberation of widely different amountsof heat in various equal-volume stages of the regenerator. Furthermore,since that part of the contaminant'to be contact material in the laterstages of the regeneration often burns less readily than the first partof the contaminant removed, it is sometimes desirable to conduct thelater part of the regeneration operation at higher temperature rangesthan the early part of the regeneration. If, as has been the practice inthe past, a means is provided for the supply or removal of heat-atsubstantially uniform and equal rates from all sections or stages ofsuch a regenerator vessel, the result is the removal of insufficientheat from those stages where the rate of combustion heat liberation isthe highest and the removal of too much heat from those stages where therate of combustion heat liberation is the lowest. As a result the rateof combustion in the overcooled sections is further retarded, therebygreatly decreasing the burning capacity of those stages and oftenresulting in incomplete removal of the contaminant from the contactmaterial.

A major object of this invention is the provision of a method oroperation for regenerators or similar vessels, wherein are conductedheat absorbing or heat liberating reactions in the presence or a movingmass of particle form contact material. utilizing supply or removal ofheat at such rates to or from the various stages of such a regeneratoror other vessel as to control the temperature of the contact materialflowing in each of said stages between those limiting temperature rangesdesirable for high rate of regeneration without catalyst damage in eachof said stages. The invention has specifically to do with the provisionof such a process, and with its attendant means of heat supply orremoval and details of its arrangement and operation.

In order to readily understand this invention, reference is made to thedrawings attached hereto in which drawings Figure 1 shows an elevationview, partially in section, of a multi-stage regenerator in which areinserted between the superposed burning stages, heat removal sectionsand coils. Figure 2 is a plan view, of this regenerator at one of theseheat removal sections and shows the arrangement of the heat transfertubes therein. Figure 3 shows an elevational view, partially in section,of a multi-stage regenerator in which a modified proportioningarrangement of burning and cooling stages is used to accomplish theproper contact material temperature control. Figure 4 is an elevationview partially in section showing a regenerator composed of a number ofburning stages each of which is equipped with independent heat transfersystems. All these drawings are diagrammatic in form.

Turning now to Figure 1, we find a multi-stage regenerator consisting ofa number of superposed burning stages l6, l1, i9, 2! and 23 of which itis superimposed directly upon I1 and between all the other burningstages are inserted cooling sections. Thus between burning stages I! andl9, l9 and 2|, and 2| and 23 are cooling sections I8, 20 and 22,respectively. Finally, below the last burning stage 23, is a largecooling section 24. 0001- ms sections i8 and 20 are identical inconstruction and each consists of two sets of hair pin shaped coils 33,one set above the other, each of which sets is made up of a number ofsuch hairpin coils uniformly spaced in parallel, side by side, acrossthe entire cross section of the cooling section, the inlet of whichcoils are connected to the common manifold 34 and the outlet of whichcoils are connected to the common manifold 35. These inlet and outletmanifolds from each set of coils in each cooling section are in turnconnected in parallel to the common inlet and outlet riser pipes 39 andMl respectively. These riser pipes connect into a single central heattransfer medium circulation and temperature control system, not shown.On the inlet to each coil is a throttle valve 36 and on the outlet ofeach coil is a pressure relief valve 31, and that part of the coilswithin the cooling section may be provided, in some cases, with fins 38which provide additional heat transfer surface. The two sets of hair pinshaped coils thus form four rows of cooling tubes uniformly spacedacross the entire cooling section cross section. In cooling section 22there is only one set of similarly arranged hair pin shaped coils, andin the final cooling section 24 there are four sets of such coils. Toeach of the burning stages are connected separate air inlet pipes 21 inwhich are flow control valves 28, and separate flue gas or air outletpipes 29. Inside the burn- Turning now to Figure 2, we find a sectionalplan view looking down on the top row of cooling tubes in a typicalcooling section. In this drawing is shown the heat transfer medium inletmanifold 34 to which are connected the inlet end of the cooling cells33, which extend across the coolin section 20 and make a downward U bend86 and return across the cooling section and out to a common outletmanifold 35. The heat transfer inlet riser pipe 39 from the heattransfer medium temperature regulating chamber and circulation pump isshown connecting into the inlet manifold Turning again to Figure 1 for astudy of the operation of the regenerator, let it be assumed for thepurpose of example, that the regenerator shown in this drawing is to beused for the burning from a contact material of a contaminant previouslydeposited in a gas oil cracking reaction. Generally such contaminantsconsist mainlyof very high molecular weight hydrocarbon compounds, thehydrogen in which will burn to vapor products, mainly steam, much morerapidly and easily than the carbon. Thus most of the hydrogen and someof the carbon are removed in the early part oi. the regeneration withthe liberation of a considerable amount of heat per weight ofcontaminant removed, leaving for the next phase 01' the regeneration adeposit consisting mainly of carbon which burns at correspondingtemperatures with considerably less readiness and with considerably lessheat liberation per unit weight of contaminant removed. After this thereis a final phase of regeneration in which it is frequently found that tosecure good removal of carbon and acceptable burning rates, higher meantemperatures of burning, i. e., a higher minimum temperature after anycooling, must be used. At the same time this requirement is frequentlycoupled with the burning of less carbon per unit volume of regeneratorthan in the second phase of regeneration. Thus although the burning maybe slow in the initial burning stage IS in which the temperature of thecontact material is low. and in which it gradually rises as the materialpasses through said stage, the burning will be very rapid in the nextflow stages and generally considerably more burning will be accomplishedand considerably more heat will be released in these early stages thanwill be accomplished in an equal volume of the later burning stages. Infact. even if equal weights of contaminant are removed in all thestages, still, for the reasons mentioned above, more heat will beliberated per equal volume of early stages than later burning stages.Thus where the burning stages are of equal size as shown in Figure 1, itis necessary to remove heat at gradually decreasing rates after eachconsecutive burning stage if the temperature level of the contactmaterial is to be maintained within the desired limits in each burningstage.

Thus, in one illustrative example of operation, the spent contactmaterial may be charged to the top of the regenerator in Figure 1 at 800F. and pass through the surge section i5 into burning section It at thattemperature. In this section the temperature of the contact material mayrise due to the heat liberated by combustion to,

say, 925 F. In this particular operation it has been founddesirable tocontrol the contact material between 950 F. and 1100 F. in the early andintermediate burning stages, the 950 minimum being high enough to givean acceptably high rate of burning for this particular contact mass andcontaminant. (Burning at substantially lower temperatures can beaccomplished, but at substantially lower rates.) Consequently, nocooling section is required for this particular operationbetween burningsections 16 and I1. With other contact materials. or with diiferentdegrees of contamination, the temperature attained in the first stagemay be different, and cooling between IB and I! may be indicated. Theheat liberated by burning in section II raises the con.- tact materialtemperature to about 1100 F. at which temperature the material flows tocooling section [8. Here it is cooled to such a temperature level aswill not-permit it to be reheated above the upper limit of 1100 F. inthe next burning zone, which in this instance happens to be about 950 F.Thus the contact material enters burning section Is at 950 F. and leavesthat section at 1100 F. and is again cooled to about 950 F. in thesubsequent cooling section 20. Note that there are roughly equal coolingloads in sections l8 and 20 and consequently equal amounts of coolingsurface. The rate of heat liberation due to burning has by this timedecreased somewhat so that in the next burning section 2|, thetemperature of the contact material only reaches about 'l 5 F. Theburning and heat liberation rate will be still lower in the next burningstage, and since the burning rate therein will be higher and the removalof the last part of the contaminant more thorough, with a higher averageburning temperature therein within the set maximum limit, the contactmaterial is only cooled to about 1025 F. in cooling section 22. whichhas onlyone set of cooling coils. It then enters burning section 23 andthe heat liberated there is only sufficient to reheat it to 1100 F..

and since in the particular example the contaminant has now beenadequately removed, no further burning sections are required. In someoperations it is desirable to hold the last of the intermediate burningstages along the regenerator at a higher average burning temperaturethan that in the first of such intermediate stages and to conduct theburning in at least the final stage in the absence of positive heatremoval.

'The contact material then enters cooling section 24 in which it must becooled to about 850 F. which is sufiiciently close to the desiredreaction vessel inlet temperature; this is a considerably higher coolingload than encountered in any of the other cooling sections and eightrows of cooling tubes are provided in this section. The above data willbe understood to be exemplary, since with other catalytic materials andwith other types and degrees of contamination, other temperatures willnecessarily be used while still following the same principle ofoperation.

The cooling system used for the regenerator in Figure 1 is one in whicha heat transfer medium such as a molten alloy or melted inorganic saltof high boiling point such as nitrates and nitrites of sodium orpotassium or certain high boiling point organic compounds in liquidstate or hot water under pressures of the order of 100 to 450 pounds persquare inch gauge, is circulated I control and circulation system. Thusheat transfer medium of approximately'the same temperature is charged toevery-cooling section. Furthermore in this type of system a relativelyhigh rate of heat transfer medium circulation is maintained through thecooling tubes so as to permit better heat transfer coefficients, moreuniform heat transfer, and so as to avoid heating the heat transfermedium to excessive temperatures, and any flow rate adjustments are of aminor nature and are not such under the circumstances as will materiallyaffect the rate of cooling by a given coil. Thus it is characteristic ofthis type of system that the major control on the amount of heattransfer in thecooling section is through regulation of the amount ofcooling surface or tubes'used in a given cooling section. Hence in theregenerator shown in Figure 1 the amount of cooling surface in thevarious cooling sections is varied dependent upon the change in rate ofburning and heat liberation in the adjacent burning sections.

Separate systems may be provided for the circulation of the same ordifferent kinds of heat transfer media to the individual coolingsystems. Thus, the nature, temperature and rate of circulation of theheat transfer medium could be varied to control the amount of heattransferred in each cooling. section. In this case, the cooling surfacedistribution in the various cooling sections could be somewhat differentthan that shown in Figure 1. With other variables the same, however, thequantity of heat removed by each cooling section would still be the sameas for the regenerator of Figure 1.

Another method of applying this invention is to increase the size orlength of each succeeding burning zone so as to compensate for thegradual decrease in burning rate and heat liberation, .so that theamount of heat liberated in each burning stage, though of differentsize, would be approximately the same. Such an arrangement would requirethe removal of substantially the same amount of heat at all the coolingsections, ex-

clusive, of course, of the ones on the inlet and outlet of theregenerator. It can be seen, however, that although the cooling is doneat nearly equal rates in each cooling stage of such an arrangement stillthe amount of cooling calculated on the volume of each burning sectionor upon v inlet pipes 21 and outlet pipes 29 and adequate internal meansof air distribution and collection. Between burning sections 42 and 44,44 and 46 and 46 and 48 are the identically constructed coolingsections43, 45 and 41 respectively. At the outlet of the regenerator is thelarge cooling section 49 which is used to adjust the contact materialtemperature to that required in the reaction vessel of the cyclicsystem. In each of cooling sections 43, 45 and 4'! are two sets ofhairpin type cooling coils 33 which constitute four rows of coolingtubes and which are connected to common manifolds and riser pipes notshown. In some cases it may be desirable to provide the coils within thecooling section with fins 38. The final cooling section 49 is of similarconstruction and has three sets of cooling coils. Spent contact materialis charged to the regenerator through pipe 26 and regenerated contactmaterial is withdrawn from the bottom of the regenerator through pipe25.

In those regenerators shown above the burning and cooling operationshave been conducted in separate independent sections of the regenerator,but the method of contact material temperature control disclosed by thisinvention is also applicable to multistage regenerators in which thecooling and burning operations are conducted in the same chambers. Sucha regenerator is shown in Figure 4 in which are shown the superimposedburning stages 5|, 52, 53, 54 and 55, the contact material inlet pipe 26and drain pipe 25.

At the top of each regeneration stage there is provided some suitableconstruction whereby a vapor disengaging space may be had, through whichcontact mass material from the zone next above may be introduced,coupled with proper isolation between zones. For clarity in the presentdiagrammatic drawing, these arrangements are reduced to a conicalpartition and single contact mass flow pipe, as indicated at 64, betweenthe several stages.

To each stage are connected independent air inlet pipes 21, distributingmeans 63 and I00 and outlet pipes 29. Each stage is also supplied withheat transfer systems consisting of uniformly distributed cooling tubes58 in the burning stage, connected to inlet manifolds 69 by means ofpipes II and to outlet manifolds 68 by means of pipes which inlet andoutlet manifolds connect to inlet and outlet circulation pipes 56 and51, respectively. Each outlet pipe 51 connects into a heat transfermedium cooler 6| which is connected to a circulation pump 62 by whichthe heat transfer medium is charged to pipe 58. Valves 59 and 60 arealso supplied to each piping system to permit control of the flow ofheat transfer medium through the cooling tubes 58. In this typeregenerator, the rate of heat removal from each stage may be controlledeither by regulation of flow of heat transfer medium through the coolingtubes 58, or if the heat transfer medium is not of the type which willpermit this, by regulation of the temperature of the heat transfermedium charged to each stage. Thus different types of heat transfermedium, or the same medium, either of which may be maintained betweendifferent temperature limits, may be used in the various independentstages. The apparatus construction and arrangement shown in Figure 4 isthe subject of my divisional application Serial Number 601,103, filed inthe United States Patent Oflice June 23, 1945.

In all the above described applications of this 1 invention the samefundamentals are involved,

namely, the provision in a multistage reactor or regenerator vessel, inwhich reactions are conducted in the presence of a moving mass ofparticle form contact material with the liberation or absorption ofheat, of a means for removing or supplying heat either to or from thevarious reaction zones of said vessels or to chambers between suchreaction zones at a sufiicient rate to control the temperature level ofthe contact material passing therethrough between those limitingtemperature ranges desired in each of the reaction stages of saidvessel. Inasmuch as the rate of heat removal from or between any givenstages of the reactor or regenerator vessel is dependent upon a greatnumber of variables such as the reactants involved and theirconcentration or partial pressure, the allowable temperature andpressures in the reaction zones, the type and nature of the contactmaterial, the rate of regeneration desired per stage, and the design ofthe reaction stages, etc., as well as upon the change in rate ofreaction and the rate of heat release or absorption as the reactionprogresses due to change in the composition of one or more of thereactants, no set dimensions or specifications for this invention can beflatly given. For each installation the rate of heat release orabsorption in each stage of the reaction vessel must be determined byexperiment or by calculation and then the proper heating and coolinginstallation for each particular stage of the reactor or regeneratorvessel, which'will supplyor remove sufficient heat to maintain thecontact material between the desired temperature ranges may becalculated by conventional methods.

It should be understood that the types of regenerators above shownand/or described and the various methods of applying this inventionabove shown are merely diagrammatic and exemplary in character and arenot meant to limit either the method of this invention or the vessels orprocesses to which it may be applied, be the reactions involved in suchprocesses either essentially endothermic or exothermic in net effect.

I claim:

1. The process for regeneration of a solid particle form contact massmaterial which has become spent by deposition of a carbonaceous depositthereon and which exists at a temperature suitable for initiatingcombustion of said deposit which process comprises: passing saidparticleform solid material downwardly through a plurality of burning zonesthrough each of which it moves as a substantially compact column ofgravitating particles, similarly passing said solid material through aheat exchange zone intermediate each two successive burning zones onlyin the intermediate and later portions of the zone series, passing anoxygen containing gas at controlled rates in direct contact with saidsolid material in the burning zones in the initial portion of the zoneseries to burn the contaminant in the absence of indirect heat exchangewith a heat exchange fluid to heat the solid material by the releasedcombustion heat to a temperature suitable for practical rapidcontaminant combustion rates but below a temperature which would causeheat damage to said solid contact material, passing an oxygen containinggas independently into direct contact with the contact material in eachof the remaining burning zones to burn off a portion of said deposit ineach burning zone, effecting a separation of the gaseous regenerationproducts formed in each burning zone from the contact material beforeany substantial amount of said gaseous products formed in any given oneof said burning zones passes into any other of said burning zones anddiscarding said separated gaseous products outside of said burningzones, passing a fluid cooling medium in indirect heat exchangerelationship with said solid material in each of said heat exchangezones, maintaining the contact material in the adjacent burning zonesbelow a heat damaging taminant burned in the corresponding preceedingposit thereon which process comprises: maintaining an elongatedsubstantially vertical confined, compact column of'said contactmaterial, withdrawing regenerated contact material from the lower end ofsaid column at a controlled rate and replenishing said column at itsupper end with spent contact material, passing an oxygen containing gasin a plurality of separate streams independently through a plurality ofburning sections at a plurality of levels along said column to effectburning of said contaminant, withdrawing gaseous regeneration productsformed in each of said burning sections from said column whilepreventing substantial flow of gaseous products formed in any givenburning section into any other of said burning sections, efiecting theheating of said spent contact material in an upper portion of saidcolumn to a temperature level conducive to practical rapid burning butbelow a contact material heat damaging level by the burning of saidcontaminant with said oxygen containin gas in the absence of indirectheat exchange with a heat exchange fluid during said heating, passing aheat exchange fluid in indirect heat transfer relationship with saidcontact material at spaced intervals along at least the intermediateportion of the length of said column. controlling the contact materialtemperature in said burning sections within the intermediate and lowerportions of said column at a level conducive for practical rapidcontaminant combustion and below a heat damaging level at leastpartially by control of the amount of said indirect heat transfer andeffecting an increase in the average burning temperature in at leastsome oi. the later burning sections in that portion of said columnprovided with said indirect heat transfer as compared with the averageburning temperature in burning sections preceding said later sectionsbut within that portion of said column provided with said indirect heattransfer and effecting completion of the contact material regenerationby burning the contaminant with air in absence of cooling by indirectheat transfer with a cooling fluid.

3. The process for regeneration of a solid particle form contact massmaterial which has become spent by deposition of a carbonaceous depositthereon which process comprises: maintaining an elongated substantiallyvertical confined, compact column of said contact material, withdrawingregenerated contact material from the lower end of said column at acontrolled rate and replenishing said column at its upper end with spentcontact material, passing an oxygen containing gas in a plurality ofseparate streams independently through a plurality of sections of saidcolumn at a plurality of levels to effect buming of said contaminant,withdrawing gaseous regeneration products formed in each of saidsections from said column while preventing substantial flow of gaseousproducts formed in any given section into any other of said sections,effecting the heating of said spent contact material in an upper portionof said column to a temperature level conducive to practical rapid.

indirect heat exchange with a heat exchange fluid, passing a heatexchange fluid in indirect as compared with the average burningtemperature in the first of said sections positioned in that portion ofsaid column below said upper portion by control of the amount of saidindirect heat transfer with said heat exchange fluid and effectingburning in at least the lowermost of said sections in said column in theabsence of cooling by indirect heat transfer with a heat exchange fluid.

4. That methodof continuously regenerating a solid particle-form contactmass material which bears a carbonaceous contaminant deposited duringits use in a hydrocarbon conversion in a system wherein the contact massis circulated cyclically through the conversion operation andregeneration which comprises the steps of flowing the contaminantbearing contact mass material as a substantially compact, continuouscolumn of gravitating solid particles downwardly through a series ofregeneration stages, admitting a controlled amount of air to each stageto accomplish burning of a predetermined amount of contaminant in eachstage, removing gaseous products of combustion from each stage outsidethereof to substantially prevent the gaseous products formed in anygiven regeneration stage from flowing through the contact mass intoadjacent stages; conducting the burning in at least the initial stage inthe absence of indirect heat transfer with a heat exchange fluid, theburning here accomplished being sufilcient to raise the contact mass toa temperature suflicient for active regeneration, but not high enough todamage the contact mass material; within the intermediate portion ofsaid regeneration stage series effecting burning of the contaminant inburning stages in the absence of cooling by indirect heat exchange andeffecting cooling of the contact material by indirect heat transfer witha cooling fluid in cooling stages at levels alternating with those ofthe burning stages while holding the last of the burning stages in saidintermediate portion of the regeneration stage series at a higheraverage burning temperature than that of the first burning stage in saidintermediate stage series but below a temperature which is damaging tothe contact material; conducting the burning in at least a final burningstage in the absence of heat removal by indirect heat transfer with aheat exchange'fluid while limiting the .total amount of contaminantburning in said final stage below that which would heat the contactmaterial to a heat damaging level.

5. A method of regenerating a solid particle form contact materialbearing a deposit consist ing of principally carbon and hydrogen which.comprises maintaining a column of said contact material, supplyingspent contact material to the upper end of said column and withdrawingregenerated contact material from the lower end of said column topromote downward flow of contact material in said column, flowingseparate diiferent vertical portions of said column to effect burning ofsaid contaminant deposit in stages, withdrawing gas from said portionswhile excluding substantial flow of gas products formed in any portionto any other portion, effecting a rapid and substantial increase in thetemperature of the spent contactmaterial supplied to the upper end ofsaid column to a temperature conducive of rapid combustion of mainly thehydrogen in the deposit along with some of the carbon by conducting theburning in the early phase of the contaminant removal in the absence ofheat removal by indirect heat transfer, removing heat from said columnto control the contact material below a heat damaging level by passing acooling fluid in indirect heat transfer relationship with said column atleast one level in that portion of the column length in which theintermediate phase of the contaminant removal occurs, conducting atleast a substantial part of the final, carbon burning phase of thecontaminant removal from the contact material flowing downwardly in saidcolumn in the absence of heat removal by indirect heat transfer with acooling fluid and maintaining the average burning temperature in theportion of the column in which the final phase of the contaminantremoval occurs higher than the average burning temperature in theportions of the column thereabove.

6'. A method of regenerating a solid particle form contact materialbearing a carbonaceous deposit which comprises, maintaining asubstantially compact column of said contact material supplyingcontaminant bearing contact material to the upper end of said column andwithdrawin regenerated contact material from the lower end to causedownward flow of contact material in said column, flowing a separatestream of combustion supporting gas through each of a plurality ofdifferent vertical sections along said column to effect burning of saidcontaminant deposit, withdrawing the gaseous combustion products fromsaid sections for gas flow while excluding substantial flow of gaseousproducts formed in any given section into any other of said sections,effecting the heating of said contact material in an upper portion ofsaid column to a temperature conducive of a high burning rate byconducting the burning in the absence of heat removal by indirect heattransfer with any cooling medium, passing a cooling fluid in indirectheat transfer relationship with the contact material in said column at aplurality of spaced apart intervals along at least the intermediateportion of the column length whereby the contact material is maintainedbelow a heat damaging level while at the same time vertical sections ofthe column between said intervals of indirect heat transfer are providedin which burning occurs in the absence of heat removal by indirect heattransfer, and restricting the cooling of the contact material at thelast interval of indirect heat transfer prior to substantial completionof the contaminant burning to a substantial higher minimum temperaturethan at any of the intervals of indirect heat transfer thereabove.

7. A method of regenerating a solid particle form contact materialbearing a carbonaceous deposit which comprises maintaining asubstantially compact column of said contact material, supplyingcontaminant bearing contact material to the upper end of said column andwithdrawing regenerated contact material from the lower end of saidcolumn to promote downward flow of contact material in said column,flowing a separate stream of combustion supporting gas through each of aplurality of sections for gas flow arranged in series along said columnto effect burning of said contaminant deposit, withdrawing gas from saidsections while excluding substantial flow of gas products formed in anysection to any other section, effecting a rapid increase in thetemperature of said contact material ln the upper portion of said columnto a level conductive ofa high burning rate by conducting the burning inthe absence of heat removal by indirect heat transfer, passing a coolingfluid in indirect heat exchange relationship with said contact materialat at least one intermediate level along the length of said column tocontrol the contact material temperature below a heat damaging levelalong the intermediate portion of said column, conducting the burning inat least one section for gas flow along the lower portion of saidcolnumn at a higher average burning temperature than in any section forgas flow thereabove in said column, and terminating the regeneration byconducting substantially the final contaminant burning in the absence ofheat removal by indirect heat transfer with a cooling fluid.

THOMAS P. SIMPSON.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,852,227 Barstow et al Apr. 5,1932 2,320,273 Gohr et a1. May 25, 1943 2,367,281 Johnson Jan. 16, 19452,374,660 Belchetz et a1. May 1, 1945 2,382,472 Frey Aug. 14, 19452,384,356 Tyson Sept. 4, 1945 2,387,936 Nicholls et al Oct. 30, 19452,409,596 Simpson et al Oct. 15, 1946 2,419,245 Arveson Apr. 22, 1947

